This invention relates to a separable electrical connector module and, more particularly, to a module of this type that includes a bore contact and coupled thereto a piston upon which gas generated during a fault-closing operation acts to drive the bore contact toward a mating rod contact, thereby to facilitate fault-closing.
In the connector of the aforesaid Tachick et al patent, the piston is provided with angularly-spaced keyways that cooperate with stationary keyribs on the bore of a conductive tubular container to prevent rotation of the piston within the module. The keyribs in the Tachick et al patent are also utilized to carry current through the module and, for this purpose, cooperate with a thin outwardly-flared tubular portion of the piston. This tubular portion, being deformed radially-inwardly when the piston is inserted into the module, tends to expand radially outwardly against the keyribs, thus providing an electrical connection between the piston and the keyribs both while the piston is stationary and while moving within the conductive tubular container. This tubular portion is typically of a highly-conductive material such as copper. The spring characteristics of the copper are relied upon to develop contact pressure against the keyribs.
I have found that under certain high current conditions, the electrical connection between the keyribs and the outward-flared tubular portion of the piston is not as good as might be desired. The keyribs provide only relatively limited contact areas, and high currents flowing through these limited contact areas can develop high magnetic forces that sometimes separate the sliding contact areas and produce undesired arcing in these regions. Another factor contributing to this undesired effect is that when the copper of the tubular portion is stressed and subjected to elevated temperatures over a long time period, it tends to yield, and such yielding reduces the contact pressure.